diff --git a/src/streamlit_app.py b/src/streamlit_app.py
index 597bd3b..442004f 100644
--- a/src/streamlit_app.py
+++ b/src/streamlit_app.py
@@ -545,11 +545,26 @@ def trading_system_page():
     with calc_tab:
         st.subheader("Position Calculator")
         
+        # Get latest portfolio value for default account size
+        portfolio_data = get_latest_portfolio_value()
+        default_account_size = portfolio_data['total_value'] if portfolio_data else 100000.0
+        
         col1, col2 = st.columns(2)
         with col1:
-            account_size = st.number_input("Account Size ($)", min_value=0.0, value=100000.0, step=1000.0)
-            risk_percentage = st.number_input("Risk Percentage (%)", min_value=0.1, max_value=100.0, value=1.0, step=0.1)
-            stop_loss_percentage = st.number_input("Stop Loss Percentage (%)", min_value=0.1, max_value=100.0, value=7.0, step=0.1)
+            account_size = st.number_input("Account Size ($)", 
+                                         min_value=0.0, 
+                                         value=default_account_size, 
+                                         step=1000.0)
+            risk_percentage = st.number_input("Risk Percentage (%)", 
+                                            min_value=0.1, 
+                                            max_value=100.0, 
+                                            value=1.0, 
+                                            step=0.1)
+            stop_loss_percentage = st.number_input("Stop Loss Percentage (%)", 
+                                                 min_value=0.1, 
+                                                 max_value=100.0, 
+                                                 value=7.0, 
+                                                 step=0.1)
         
         with col2:
             entry_price = st.number_input("Entry Price ($)", min_value=0.01, step=0.01)